Hypervelocity fluid flow temperature limiter



Aug. 1962 D. J. KATSANIS 3,050,000

HYPERVELOCITY FLUID FLOW TEMPERATURE LIMITER Filed Dec. 23, 1958 W .S m W m M N E a R V J m mK A J. m R V m NZ Y 0% B United States Patent s a HYPERvELocrrv riilm FLow TEMPERATURE LIMITER David J. Katsanis, Philadelphia, Pa, assignor to the United States of America as represented by the Secretary of the Army Filed Dec. 23, 1958, Ser. No. 782,608 4 Claims. (Cl. 102-925) (Granted under Title 35, US. Code (1952), see. 266) with a material which is liquified or vaporizedby atmospheric friction and functions to prevent overheating of the cone upon its return from space. The use of this coating has not been altogether satisfactory largely for the reason that it is likely to be exhausted before the danger of overheating is past. In accordance with the present invention, this dilficulty is avoided by feeding to the forward surface of the cone a material whiclr is liquified or vaporized by atmospheric friction and flows rearwardly over the cones exterior surface. As hereinafter explained, the feeding of this cooling material to the forward surface of the cone is initiated by the heat incident to the cones return from outer space to the atmosphere.

The invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope is indicated by the appended claims.

Referring to the drawings:

FIG. 1 is a partial section view of a preferred form of the invention, and

FIG. 2 illustrates a modification.

The missile includes a casing 10 which has at one end fins 11 and at the other end a cone 12 which may be provided with a ceramic coating 13. Enclosed in the casing 10 are a tank 14 to contain one type of fuel, and a tank 15 to contain another type of fuel; The tanks 14 and 15 have a central aperture adapted to receive a rod 16.

The rod 16 consists of a material such as copper, silver, gold or lead, which melts at a relatively low temperature. It has an external thread 17 which engages an internal thread of a collar 18. This collar is rotatable in a bearing 19 which is fixed to the cone '12 by a spider 20. A gear 21 keyed to the collar 18 meshes with a gear 22 keyed to the shaft of a motor 23 which is supported on the spider 20 or in any other suitable manner.

Power for operating the motor 23 is derived from a source 24 through a relay 25. This relay'is controlled by a thermostat 26 located at the forward end of the rod 16. So long as the forward end of this rod does not exceed a predetermined temperature the output of the thermostat is insufdcient to close the relay 25. When this temperature is exceeded, however, the relay is closed, the motor is energized and the collar is rotated in a direction to feed the rod 16 outwardly toward the cone 12 at a controlled rate.

As a result of this feeding of the rod 16 into the region of high temperature fluid flow, the material of the rod 3,0503% Patented Aug. 21, 1962 assumes an aerodynamic shape conforming to the conditions of the fluid flow. This shape is achieved spontaneously as the rod melts or vaporizes in the flow. The heat transferred to the rod material as it changes phase reduces the stagnation temperature, and provides additional cooling as it flows rearwardly over the cone 12. The relay switch initially closed by the temperature responsive means 26 should stay closed to keep the motor 23 running after the circuit from such means has been opened by the outer end of the rod 16 having melted, as is understood by those familiar with the art of thermostats, and relays.

The modification of FIG. 2 is similar to that of FIG. 1 in most respect-s but differs therefrom in that the thermostat 26 is located near the surface of the nose cone. When the forward end of the rod exceeds a predetermined temperature the thermostat is adjusted so that it closes the relay 25 and energizes the motor 23 to feed the rod '16 as before. However if the missile should slow down or leave the atmosphere again and cause the temperature to drop so that the rod would not melt in the air flow the thermostat would open the relay causing the motor to stop. This cycle could be repeated until the entire rod is melted.

The invention has utility in connection with projectiles, missiles, satellites and other objects which move through the atmosphere at supersonic or hypervelocities. In such cases, it operates to preserve aerodynamic shape, reduce drag and protect delicate instruments and other parts from -the deleterious effects of high temperatures. As will be apparent to those skilled in the art, it also has application in other situations where the'limitation of a local temperature is required.

Of the materials mentioned above, copper is preferred because the sum of its latent heats of fusion and vaporization is higher than that of the other metals mentioned. The rate of feed is at a rate of about 10 feet per second and upwardly, but needs to be continued for only a very few seconds. Where a lower melting temperature is desired lead is preferred.

I claim:

1. In a missile adapted to travel in space and having a tubular body with a cone truncated to provide an opening at its forward end, the combination therewith of means for dissipating the heat generated by atmospheric friction upon the return of said missile to the atmosphere, said heat dissipating means including a rod movably supported in said-body and extending outwardly through and substantially filling said opening, said rod consisting of a material having low temperatures of fusion and vaporization with the sum of the latent heats of fusion and vaporization being high, means for feeding said rod outwardly through said opening, and temperature responsive means mounted adjacent a forward portion of said cone for actuating said rod feeding means.

2. A missile according to claim 1 wherein said cone has a ceramic coating and said temperature responsive means is located in said coating.

3. A missile according to claim 1 in which said temperature responsive means is mounted on said rod.

4. A missile according to claim 1 in which said temperature responsive means is mounted on said cone.

References Cited in the file of this patent Leghorn Apr. 27, 1948 

